4 files changed, 49 insertions, 15 deletions

diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 63d51274dfbf..1bbe97c2a632 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -76,6 +76,7 @@ extern int cifs_revalidate_file(struct file *filp);
 extern int cifs_revalidate_dentry(struct dentry *);
 extern int cifs_invalidate_mapping(struct inode *inode);
 extern int cifs_revalidate_mapping(struct inode *inode);
+extern int cifs_zap_mapping(struct inode *inode);
 extern int cifs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 extern int cifs_setattr(struct dentry *, struct iattr *);
 
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 69da55b750e7..630e0f4b2c66 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1118,6 +1118,7 @@ struct cifsInodeInfo {
 #define CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2 (2) /* Downgrade oplock to L2 */
 #define CIFS_INO_DELETE_PENDING           (3) /* delete pending on server */
 #define CIFS_INO_INVALID_MAPPING          (4) /* pagecache is invalid */
+#define CIFS_INO_LOCK                     (5) /* lock bit for synchronization */
         unsigned long flags;
         spinlock_t writers_lock;
         unsigned int writers;           /* Number of writers on this inode */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c8a570e87900..208f56eca4bf 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -335,7 +335,7 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
         spin_unlock(&cifs_file_list_lock);
 
         if (fid->purge_cache)
-                cifs_invalidate_mapping(inode);
+                cifs_zap_mapping(inode);
 
         file->private_data = cfile;
         return cfile;
@@ -1529,7 +1529,7 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u32 type,
                  */
                 if (!CIFS_CACHE_WRITE(CIFS_I(inode)) &&
                                         CIFS_CACHE_READ(CIFS_I(inode))) {
-                        cifs_invalidate_mapping(inode);
+                        cifs_zap_mapping(inode);
                         cifs_dbg(FYI, "Set no oplock for inode=%p due to mand locks\n",
                                  inode);
                         CIFS_I(inode)->oplock = 0;
@@ -2218,7 +2218,7 @@ int cifs_strict_fsync(struct file *file, loff_t start, loff_t end,
                  file->f_path.dentry->d_name.name, datasync);
 
         if (!CIFS_CACHE_READ(CIFS_I(inode))) {
-                rc = cifs_invalidate_mapping(inode);
+                rc = cifs_zap_mapping(inode);
                 if (rc) {
                         cifs_dbg(FYI, "rc: %d during invalidate phase\n", rc);
                         rc = 0; /* don't care about it in fsync */
@@ -2649,7 +2649,7 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
                  * request comes - break it on the client to prevent reading
                  * an old data.
                  */
-                cifs_invalidate_mapping(inode);
+                cifs_zap_mapping(inode);
                 cifs_dbg(FYI, "Set no oplock for inode=%p after a write operation\n",
                          inode);
                 cinode->oplock = 0;
@@ -3112,7 +3112,7 @@ int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
         xid = get_xid();
 
         if (!CIFS_CACHE_READ(CIFS_I(inode))) {
-                rc = cifs_invalidate_mapping(inode);
+                rc = cifs_zap_mapping(inode);
                 if (rc)
                         return rc;
         }
@@ -3670,7 +3670,7 @@ void cifs_oplock_break(struct work_struct *work)
                 if (!CIFS_CACHE_READ(cinode)) {
                         rc = filemap_fdatawait(inode->i_mapping);
                         mapping_set_error(inode->i_mapping, rc);
-                        cifs_invalidate_mapping(inode);
+                        cifs_zap_mapping(inode);
                 }
                 cifs_dbg(FYI, "Oplock flush inode %p rc %d\n", inode, rc);
         }
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index ff420b275777..9ff8df8b4d84 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -22,6 +22,7 @@
 #include <linux/stat.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include <linux/freezer.h>
 #include <asm/div64.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
@@ -1762,29 +1763,60 @@ int
 cifs_invalidate_mapping(struct inode *inode)
 {
         int rc = 0;
-        struct cifsInodeInfo *cifs_i = CIFS_I(inode);
-
-        clear_bit(CIFS_INO_INVALID_MAPPING, &cifs_i->flags);
 
         if (inode->i_mapping && inode->i_mapping->nrpages != 0) {
                 rc = invalidate_inode_pages2(inode->i_mapping);
-                if (rc) {
+                if (rc)
                         cifs_dbg(VFS, "%s: could not invalidate inode %p\n",
                                  __func__, inode);
-                        set_bit(CIFS_INO_INVALID_MAPPING, &cifs_i->flags);
-                }
         }
 
         cifs_fscache_reset_inode_cookie(inode);
         return rc;
 }
 
+/**
+ * cifs_wait_bit_killable - helper for functions that are sleeping on bit locks
+ * @word: long word containing the bit lock
+ */
+static int
+cifs_wait_bit_killable(void *word)
+{
+        if (fatal_signal_pending(current))
+                return -ERESTARTSYS;
+        freezable_schedule_unsafe();
+        return 0;
+}
+
 int
 cifs_revalidate_mapping(struct inode *inode)
 {
-        if (test_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(inode)->flags))
-                return cifs_invalidate_mapping(inode);
-        return 0;
+        int rc;
+        unsigned long *flags = &CIFS_I(inode)->flags;
+
+        rc = wait_on_bit_lock(flags, CIFS_INO_LOCK, cifs_wait_bit_killable,
+                                TASK_KILLABLE);
+        if (rc)
+                return rc;
+
+        if (test_and_clear_bit(CIFS_INO_INVALID_MAPPING, flags)) {
+                rc = cifs_invalidate_mapping(inode);
+                if (rc)
+                        set_bit(CIFS_INO_INVALID_MAPPING, flags);
+        }
+
+        clear_bit_unlock(CIFS_INO_LOCK, flags);
+        smp_mb__after_clear_bit();
+        wake_up_bit(flags, CIFS_INO_LOCK);
+
+        return rc;
+}
+
+int
+cifs_zap_mapping(struct inode *inode)
+{
+        set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(inode)->flags);
+        return cifs_revalidate_mapping(inode);
 }
 
 int cifs_revalidate_file_attr(struct file *filp)